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Background: Diabetic ulcers (DUs) are characterized by chronic inflammation and delayed re-epithelialization, with a high incidence and weighty economic burden. The primary therapeutic strategies for refractory wounds include surgery, non-invasive wound therapy, and drugs, while the optimum regimen remains controversial. Sirtuin-6 (SIRT6) is a histone deacetylase and a key epigenetic factor that exerts anti-inflammatory and pro-proliferatory effects in wound healing. However, the exact function of SIRT6 in DUs remains unclear., Methods: We generated tamoxifen-inducible SIRT6 knockout mice by crossing SIRT6 flox/flox homozygous mice with UBC-creERT2 + transgenic mice. Systemic SIRT6 null mice, under either normal or diabetic conditions, were utilized to assess the effects of SIRT6 in DUs treatment. Gene and protein expressions of SIRT6 and inflammatory cytokines were measured by Western blotting and RT-qPCR. Histopathological examination confirmed the altered re-epithelialization (PCNA), inflammation (NF-κB p50 and F4/80), and angiogenesis (CD31) markers during DUs restoration., Results: Knockout of SIRT6 inhibited the healing ability of DUs, presenting attenuated re-epithelialization (PCNA), exacerbated inflammation responses (NF-κB p50, F4/80, Il-1β, Tnf-α, Il-6, Il-10, and Il-4), and hyperplasia vascular (CD31) compared with control mice., Conclusions: SIRT6 could boost impaired wound healing through improving epidermal proliferation, inflammation, and angiogenesis. Our study highlighted the therapeutic potential of the SIRT6 agonist for DUs treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The effects and underlying mechanisms of adolescent exposure to combined environmental hazards on cognitive function remain unclear. Here, using a combined exposure model, we found significant cognitive decline, hippocampal neuronal damage, and neuronal senescence in mice exposed to cadmium (Cd) and high-fat diet (HFD) during adolescence. Furthermore, we observed a significant downregulation of Sirtuin 6 (SIRT6) expression in the hippocampi of co-exposed mice. UBCS039, a specific SIRT6 activator, markedly reversed the above adverse effects. Further investigation revealed that co-exposure obviously reduced the levels of La ribonucleoprotein 7 (LARP7), disrupted the interaction between LARP7 and SIRT6, ultimately decreasing SIRT6 expression in mouse hippocampal neuronal cells. Overexpression of Larp7 reversed the combined exposure-induced SIRT6 decrease and senescence in mouse hippocampal neuronal cells. Additionally, the results showed notably elevated levels of Larp7 m6A and YTH domain family protein 2 (YTHDF2) in mouse hippocampal neuronal cells treated with the combined hazards. Ythdf2 short interfering RNA, RNA immunoprecipitation, and RNA stability assays further demonstrated that YTHDF2 mediated the degradation of Larp7 mRNA under combined exposure. Collectively, adolescent co-exposure to Cd and HFD causes hippocampal senescence and cognitive decline in mice by inhibiting LARP7-mediated SIRT6 expression in an m6A-dependent manner., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Several metabolites have been shown to have independent and at times unexpected biological effects outside of their metabolic pathways. These include succinate, lactate, fumarate, and 2-hydroxyglutarate. 2-Hydroxybutyrate (2HB) is a byproduct of endogenous cysteine synthesis, produced during periods of cellular stress. 2HB rises acutely after exercise; it also rises during infection and is also chronically increased in a number of metabolic disorders. We show here that 2HB inhibits branched-chain aminotransferase enzymes, which in turn triggers a SIRT4-dependent shift in the compartmental abundance of protein ADP-ribosylation. The 2HB-induced decrease in nuclear protein ADP-ribosylation leads to a C/EBPβ-mediated transcriptional response in the branched-chain amino acid degradation pathway. This response to 2HB exposure leads to an improved oxidative capacity in vitro. We found that repeated injection with 2HB can replicate the improvement to oxidative capacity that occurs following exercise training. Together, we show that 2-HB regulates fundamental aspects of skeletal muscle metabolism., Competing Interests: BW, ML, EM, PC, VE, CB, CA, SS, EM, PK, JR, HR, JL, RJ No competing interests declared, (© 2023, Wadsworth et al.)

MitoAMPK was proved to inhibit the Warburg effect, but the specific mechanisms on non-small-cell lung cancer remain unclear. Here, we selected SIRT6 and MZF1 to clarify the mechanism. By western blotting, quantitative polymerase chain reaction, the CCK-8 assay, and immunohistochemistry assays, we found SIRT6 expression was lower in NSCLC tissues and cell lines than normal tissues and cells. Moreover, SIRT6 could inhibit the Warburg effect by regulating glycolysis-related genes of SLC2A2, SLC2A4 and PKM2. Finally, we demonstrated the interaction between SIRT6 and MZF1 using ChIP-qPCR. In conclusion, mitoAMPK inhibits the Warburg effect by regulating the expression of the MZF1-SIRT6 complex., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Aging is a process of time-associated depletion in the physiological functions, essential for the survival and reproducibility of living beings. Some age-related disorders can be successfully controlled with some biomedical techniques or pharmaceutical approaches. There are some precise remedies that demonstrate conspicuous promise in the preclinical and clinical setup of extending lifespan or enhancing health by altering natural senescence. The sirtuin family of proteins is one of the most favorable targets for antiaging strategies. Sirtuins were initially identified as transcription repressors in yeast, but today they are known to exist in bacteria and eukaryotes, as well as humans. The SIRT (1-7) family of proteins in humans is made up of seven members, each of which has either mono-ADP ribosyl transferase or deacetylase activity. Researchers suggest that sirtuins are essential for cell metabolism and play a major role in how cells react to various stimuli, such as oxidative or genotoxic stress. A healthy lifestyle, which includes exercise and a balanced diet, has been demonstrated to impact health span by adjusting the levels of sirtuins, suggesting the involvement of sirtuins in extending human longevity. The hunt for sirtuin activators is among the most extensive and comprehensive research subjects in the present scenario. Some optimism has been generated to investigate antiaging therapies by natural compounds, such as curcumin and others. This review article highlights the role of sirtuins in native senescence and their primordial roles in the progression of several life-threatening diseases. Further, it also provides recent information on the sirtuin activators and inhibitors and their therapeutic benefits., (© 2024 Wiley Periodicals LLC.)

Diabetic kidney disease (DKD) is a complication of diabetic mellitus. New treatments need to be developed. This study aimed to investigate the effects of quercetin-4'-O-β-D-glucopyranoside (QODG) on podocyte injury. Podocytes were cultured in high glucose (HG) medium, treated with QODG, and overexpressing or knocking down SIRT5. Oxidative stress indicators were assessed using corresponding kits. Pyroptosis was detected by flow cytometry and western blot analysis. Succinylation modification was detected using immunoprecipitation (IP) and western blot analysis. The interaction between NEK7 and NLRP3 was determined by co-IP. The results indicated that QODG inhibited oxidative stress and pyroptosis of podocytes induced by HG. Besides, QODG suppressed succinylation levels in HG-induced podocytes, with the upregulation of SIRT5. Knockdown of SIRT5 reversed the effects of QODG on oxidative stress and pyroptosis. Moreover, SIRT5 inhibited the succinylation of NEK7 and the interaction between NLRP3 and NEK7. In conclusion, QODG upregulates SIRT5 to inhibit the succinylation modification of NEK7, impedes the interaction between NEK7 and NLRP3, and then inhibits the pyroptosis and oxidative stress injury of podocytes under HG conditions. The findings suggested that QODG has the potential to treat DKD and explore a novel underlying mechanism of QODG function., (© 2024 John Wiley & Sons Australia, Ltd.)

The kidney is a metabolically active organ that requires energy to drive processes such as tubular reabsorption and secretion, and shows a decline in function with advancing age. Various molecular mechanisms, including genomic instability, telomere attrition, inflammation, autophagy, mitochondrial function, and changes to the sirtuin and Klotho signalling pathways, are recognized regulators of individual lifespan and pivotal factors that govern kidney ageing. Thus, mechanisms that contribute to ageing not only dictate renal outcomes but also exert a substantial influence over life expectancy. Conversely, kidney dysfunction, in the context of chronic kidney disease (CKD), precipitates an expedited ageing trajectory in individuals, leading to premature ageing and a disconnect between biological and chronological age. As CKD advances, age-related manifestations such as frailty become increasingly conspicuous. Hence, the pursuit of healthy ageing necessitates not only the management of age-related complications but also a comprehensive understanding of the processes and markers that underlie systemic ageing. Here, we examine the hallmarks of ageing, focusing on the mechanisms by which they affect kidney health and contribute to premature organ ageing. We also review diagnostic methodologies and interventions for premature ageing, with special consideration given to the potential of emerging therapeutic avenues to target age-related kidney diseases., (© 2024. Springer Nature Limited.)

Infertility is intricately linked with alterations in circadian rhythms along with physiological decline and stem cell senescence. Yet, the direct involvement of circadian mechanisms in nicotine-induced injury to the testes, especially the senescence of spermatogonia stem cells (SSCs), is not well comprehended. This study revealed that nicotine exposure induced testis injury by triggering SSCs senescence along with the upregulation of senescence marker genes and senescence-associated secretory phenotype components. Moreover, nicotine treatment caused mitochondrial hyper-fusion, increased oxidative stress, and DNA damage. Exposure to nicotine was found to suppress the expression of sirtuin 6 (SIRT6), which accelerated the senescence of spermatogonia stem cells (SSCs). This acceleration led to increased acetylation of brain and muscle ARNT-like protein (Bmal1), consequently reducing the expression of Bmal1 protein. Conversely, the overexpression of Bmal1 alleviated mitochondrial hyper-fusion and senescence phenotypes induced by nicotine. Overall, this study unveiled a novel molecular mechanism behind nicotine-induced disorders in spermatogenesis and highlighted the SIRT6/Bmal1 regulatory pathway as a potential therapeutic target for combating nicotine-associated infertility., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organization that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitle., (Copyright © 2024. Published by Elsevier Inc.)

Ischemic stroke (IS) is a dangerous cerebrovascular disorder with a significant incidence and death rate. Ubiquitin-specific peptidase 18 (USP18) has been proven to mitigate ischemic brain damage; however, its potential regulatory mechanisms remain unclear. In vivo and in vitro models of IS were established by middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R). Neurocyte injury was detected by MTT, LDH, ROS level, mitochondrial membrane potential (Δψm), and flow cytometry. Molecular expression was evaluated by qPCR, Western blotting, and immunofluorescence staining. Molecular mechanisms were determined by Co-IP, RIP, and MeRIP. IS injury was determined by neurological behavior score and TTC staining. Mitophagy was observed by TEM. USP18 and fat mass and obesity-associated protein (FTO) expression declined after OGD/R. Dysfunctional mitochondrial and apoptosis in OGD/R-stimulated neurocytes were eliminated by USP18/FTO overexpression via mitophagy activation. USP18-mediated de-ubiquitination was responsible for increasing FTO protein stability. Up-regulation of FTO protein restrained m6A modification of sirtuin6 (SIRT6) in a YTHDF2-dependent manner to enhance SIRT6 expression and subsequent activation of AMPK/PGC-1α/AKT signaling. FTO induced mitophagy to ameliorate nerve cell damage through SIRT6/AMPK/PGC-1α/AKT pathway. Finally, USP18/FTO overexpression relieved IS in rats via triggering SIRT6/AMPK/PGC-1α/AKT axis-mediated mitophagy. USP18 increased FTO protein stability to trigger SIRT6-induced mitophagy, thus mitigating IS. Our data unravel the novel neuroprotective mechanism of USP18 and suggest its potential as a promising treatment target for IS., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Myocardial infarction (MI) is a prevalent form of ischemic heart disease, significantly contributing to heart disease-related deaths worldwide. This condition is primarily caused by myocardial ischemic-reperfusion injury (MIRI). Sirtuin 5 (SIRT5) is a desuccinylase known for its ability to reduce protein succinylation. Recent studies have highlighted the potential role of SIRT5 in various human diseases, including MIRI. This study aims to investigate the specific role of SIRT5 in modulating autophagy and cardiomyocyte death in a MIRI model, as well as to identify the downstream protein targets of SIRT5. Initially, we established a hypoxia/reoxygenation (H/R)-induced MIRI cell model to measure SIRT5 expression and assess its functions. Our results indicated that H/R induction led to a downregulation of SIRT5 expression, decreased autophagy, and increased cell death. Notably, overexpression of SIRT5 effectively promoted autophagy and inhibited cell death in the MIRI cell model. Mechanistically, SIRT5 was found to directly interact with the target of myb1 membrane trafficking protein (TOM1) at the K48 site, inducing its desuccinylation and stabilization. Further rescue assays revealed that TOM1 knockdown reversed the changes in autophagy and apoptosis caused by SIRT5 overexpression in the MIRI cell model. In vivo experiments demonstrated that SIRT5 alleviated myocardial injury in MI models. In conclusion, this study uncovers the role of SIRT5-mediated desuccinylation of TOM1 in regulating autophagy-related cell death in MIRI, providing new insights into potential therapeutic strategies for MI., (© 2024. The Author(s).)

Melanoma, arising from the malignant transformation of melanocytes, stands as the most lethal type of skin cancer. While significant strides have been made in targeted therapy and immunotherapy, substantially enhancing therapeutic efficacy, the prognosis for melanoma patients remains unoptimistic. SIRT7, a nuclear-localized deacetylase, plays a pivotal role in maintaining cellular homeostasis and adapting to external stressors in melanoma, with its activity closely tied to intracellular nicotinamide adenine dinucleotide (NAD + ). However, its involvement in adaptive resistance to targeted therapy remains unclear. Herein, we unveil that up-regulated SIRT7 promotes mitochondrial biogenesis to render the adaptive resistance to MAPK inhibition in melanoma. Initially, we observed a significant increase of SIRT7 expression in publicly available datasets following targeted therapy within a short duration. In consistent, we found elevated SIRT7 expression in melanoma cells subjected to BRAF or MEK inhibitors in vitro. The up-regulation of SIRT7 expression was also confirmed in xenograft tumors in mice after targeted therapy in vivo. Furthermore, we proved that SIRT7 deficiency led to decreased cell viability upon prolonged exposure to BRAF or MEK inhibitors, accompanied by an increase in cell apoptosis. Mechanistically, SIRT7 deficiency restrained the upregulation of genes associated with mitochondrial biogenesis and intracellular ATP levels in response to targeted therapy treatment in melanoma cells. Ultimately, we proved that SIRT7 deficieny could sensitize BRAF-mutant melanoma cells to MAPK inhibition targeted therapy in vivo. In conclusion, our findings underscore the role of SIRT7 in fostering adaptive resistance to targeted therapy through the facilitation of mitochondrial biogenesis. Targeting SIRT7 emerges as a promising strategy to overcome MAPK inhibitor adaptive resistance in melanoma., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Gemcitabine serves as a first-line chemotherapeutic treatment for pancreatic cancer (PC), but it is prone to rapid drug resistance. Increasing the sensitivity of PC to gemcitabine has long been a focus of research. Fasting interventions may augment the effects of chemotherapy and present new options. SIRT7 is known to link metabolism with various cellular processes through post-translational modifications. We found upregulation of SIRT7 in PC cells is associated with poor prognosis and gemcitabine resistance. Cross-analysis of RNA-seq and ATAC-seq data suggested that GLUT3 might be a downstream target gene of SIRT7. Subsequent investigations demonstrated that SIRT7 directly interacts with the enhancer region of GLUT3 to desuccinylate H3K122. Our group's another study revealed that GLUT3 can transport gemcitabine in breast cancer cells. Here, we found GLUT3 KD reduces the sensitivity of PC cells to gemcitabine, and SIRT7 KD-associated gemcitabine-sensitizing could be reversed by GLUT3 KD. While fasting mimicking induced upregulation of SIRT7 expression in PC cells, knocking down SIRT7 enhanced sensitivity to gemcitabine through upregulating GLUT3 expression. We further confirmed the effect of SIRT7 deficiency on the sensitivity of gemcitabine under fasting conditions using a mouse xenograft model. In summary, our study demonstrates that SIRT7 can regulate GLUT3 expression by binding to its enhancer and altering H3K122 succinylation levels, thus affecting gemcitabine sensitivity in PC cells. Additionally, combining SIRT7 knockdown with fasting may improve the efficacy of gemcitabine. This unveils a novel mechanism by which SIRT7 influences gemcitabine sensitivity in PC and offer innovative strategies for clinical combination therapy with gemcitabine., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Patient age is critical for mesenchymal stem cell quality and differentiation capacity. We demonstrate that proliferation and adipogenic capacity of subcutaneous adipose stem cells (ASCs) from female patients declined with advanced age, associated with reduction in cell nucleus size, increase in nuclear lamina protein lamin B1/B2, and lamin A, upregulation of senescence marker p16INK4a and senescence-associated β-galactosidase activity. Adipogenic induction resulted in differentiation of adipocytes and upregulation of adipogenic genes CCAAT enhancer binding protein alpha, fatty acid binding protein 4, lipoprotein lipase, and peroxisome proliferator-activated receptor-γ, which was not affected by the Sirt-1 activator YK-3-237 or the Sirt-1 inhibitor EX-527. Protein expression of the stem cell markers Oct4 and Sox2 was not significantly downregulated with advanced patient age. Mitochondrial reactive oxygen species were increased in ASCs from old-aged patients, whereas protein expression of NADPH oxidases NOX1 and NOX4 was downregulated, and dual oxidase isoforms remained unchanged. Generation of nitric oxide and iNOS expression was downregulated. Protein expression of Sirt-1 and Sirt-3 decreased with patient age, whereas Sirt-2 and Sirt-5 remained unchanged. Induction of adipogenesis stimulated protein expression of Sirt-1 and Sirt-3, which was not affected upon pre-incubation with the Sirt-1-activator YK-3-237 or the Sirt-1-inhibitor EX-527. The Sirt-1 inhibitor Sirtinol downregulated adiponectin protein expression and the number of adipocytes, whereas YK-3-237 exerted stimulatory effects. In summary, our data demonstrate increased oxidative stress in ASCs of aging patients, and decline of adipogenic capacity due to Sirt-1- mediated adiponectin downregulation in elderly patients., (© 2024. The Author(s).)

The nucleolus has core functions in ribosome biosynthesis, but also acts as a regulatory hub in a plethora of non-canonical processes, including cellular stress. Upon DNA damage, several DNA repair factors shuttle between the nucleolus and the nucleoplasm. Yet, the molecular mechanisms underlying such spatio-temporal protein dynamics remain to be deciphered. Here, we present a novel imaging platform to investigate nucleolar-nucleoplasmic protein shuttling in living cells. For image acquisition, we used a commercially available automated fluorescence microscope and for image analysis, we developed a KNIME workflow with implementation of machine learning-based tools. We validated the method with different nucleolar proteins, i.e., PARP1, TARG1 and APE1, by monitoring their shuttling dynamics upon oxidative stress. As a paradigm, we analyzed PARP1 shuttling upon H2O2 treatment in combination with a range of pharmacological inhibitors in a novel reporter cell line. These experiments revealed that inhibition of SIRT7 results in a loss of nucleolar PARP1 localization. Finally, we unraveled specific differences in PARP1 shuttling dynamics after co-treatment with H2O2 and different clinical PARP inhibitors. Collectively, this work delineates a highly sensitive and versatile bioimaging platform to investigate swift nucleolar-nucleoplasmic protein shuttling in living cells, which can be employed for pharmacological screening and in-depth mechanistic analyses., (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Segmental bone defects and nonunion of fractures caused by trauma, infection, tumor or systemic diseases with limited osteogenesis and prolonged bone healing cycles are challenging issues in orthopedic clinical practice. Therefore, identifying regulatory factors for bone tissue regeneration and metabolism is crucial for accelerating bone repair and reconstructing defective areas. Silence information regulator 6 (SIRT6), functioning as a deacetylase and nucleotide transferase, is extensively involved in the regulation of differentiation, apoptosis, metabolism, and inflammation in bone cells including osteoblasts and osteoclasts, and is considered to be an important factor in regulating bone metabolism. SIRT6 forms a complex with B lymphocyte-induced maturation protein 1 (Blimp1), down-regulates the expression of the nuclear factor κB (NF-κB) pathway, and promotes the expression of the ERα-FasL axis signal to inhibit osteoclast formation and maturation differentiation, thereby hindering bone resorption and increasing bone mass. In addition, SIRT6 activates the Akt-mTOR pathway to regulate the autophagy level and osteogenesis of bone marrow mesenchymal stem cells, inhibits glycolysis and reactive oxygen production in osteoblasts, promotes osteoblast differentiation through the CREB/CCN1/COX2 pathway and the bone morphogenetic protein (BMP) signaling pathway, enhances bone formation, and accelerates bone regeneration and repair of skeletal tissue. This article provides an overview of the research progress on SIRT6 in the pathophysiology of bone regeneration, revealing its potential as a novel therapeutic target for bone tissue repair to alleviate the progression of skeletal pathological diseases.

Vascular dementia (VaD) is a prevalent form of dementia resulting from chronic cerebral hypoperfusion (CCH). However, the pathogenic mechanisms of VaD and corresponding therapeutic strategies are not well understood. Sirtuin 6 (SIRT6) has been implicated in various biological processes, including cellular metabolism, DNA repair, redox homeostasis, and aging. Nevertheless, its functional relevance in VaD remains unexplored. In this study, we utilized a bilateral common carotid artery stenosis (BCAS) mouse model of VaD to investigate the role of SIRT6. We detected a significant decrease in neuronal SIRT6 protein expression following CCH. Intriguingly, neuron-specific ablation of Sirt6 in mice exacerbated neuronal damage and cognitive deficits after CCH. Conversely, treatment with MDL-800, an agonist of SIRT6, effectively mitigated neuronal loss and facilitated neurological recovery. Mechanistically, SIRT6 inhibited excessive mitochondrial fission by suppressing the CCH-induced STAT5-PGAM5-Drp1 signaling cascade. Additionally, the gene expression of monocyte SIRT6 in patients with asymptomatic carotid stenosis showed a correlation with cognitive outcomes, suggesting translational implications in human subjects. Our findings provide the first evidence that SIRT6 prevents cognitive impairment induced by CCH, and mechanistically, this protection is achieved through the remodeling of mitochondrial dynamics in a STAT5-PGAM5-Drp1-dependent manner., (© 2024. The Author(s).)

Sirtuin 5 (SIRT5) is increasingly recognized as a key regulator of cellular metabolism, which is commonly dysregulated in cancer cells, resulting in enhanced proliferation and tumor progression. To investigate the clinicopathologic implications of SIRT5 dysregulation in glioblastoma, we performed comprehensive analyses of transcriptomic data and functional verifications using in vitro and in vivo glioblastoma models. We found that higher SIRT5 expression levels were associated with a favorable prognosis in glioma patients. Knockdown of SIRT5 significantly enhanced glioblastoma cell growth. Our data suggest its potential role in regulating mitochondrial metabolism in gliomas. Furthermore, SIRT5 is also significantly correlated with synaptic remodeling pathways. Our findings indicate a tumor-suppressive role for SIRT5 that extends beyond regulating cancer metabolism, by which it may function through modulating neuroplasticity. Understanding these cellular interactions provides nuanced insights into the multifaceted role of SIRT5 and the broader therapeutic implications of this for the development of novel treatment strategies.

Cuproptosis is characterized by lipoylated protein aggregation and loss of iron-sulfur (Fe-S) proteins, which are crucial for a wide range of important cellular functions, including DNA replication and damage repair. Sirt2 and sirt4 are lipoamidases that remove the lipoyl moiety from lipoylated proteins using nicotinamide adenine dinucleotide (NAD + ) as a cofactor. However, to date, it is not clear whether nicotinamide mononucleotide (NMN), a precursor of NAD + , affects cellular sensitivity to cuproptosis. Therefore, in the current study, cuproptosis was induced by the copper (Cu) ionophore elesclomol (Es) in HeLa cells. It was also found that Es/Cu treatment increased cellular DNA damage level. On the other hand, NMN treatment partially rescued cuproptosis in a dose-dependent manner, as well as reduced cellular DNA damage level. In addition, NMN upregulated the expression of Fe-S protein POLD1, without affecting the aggregation of lipoylated proteins. Mechanistic study revealed that NMN increased the expression of sirt2 and cellular reduced nicotinamide adenine dinucleotide phosphate (NADPH) level. Overexpression of sirt2 and sirt4 did not change the aggregation of lipoylated proteins, however, sirt2, but not sirt4, increased cellular NADPH levels and partially rescued cuproptosis. Inhibition of NAD + kinase (NADK), which is responsible for generating NADPH, abolished the rescuing function of NMN and sirt2 for Es/Cu induced cell death. Taken together, our results suggested that DNA damage is a characteristic feature of cuproptosis. NMN can partially rescue cuproptosis by upregulating sirt2, increase intracellular NADPH content and maintain the level of Fe-S proteins, independent of the lipoamidase activity of sirt2., (© 2024. The Author(s).)

Introduction: Ulcerative colitis (UC) is a primary culprit of inflammatory bowel disease that entails prompt and effective clinical intervention. Remdesivir (RDV), a broad-spectrum antiviral nucleotide, has been found to exert anti-inflammatory effects in experimental animals., Aim: This study investigates the prospective anti-inflammatory merit of RDV on an experimental model of UC. The role of SIRT6/FoxC1 in regulating colonic cell inflammation and pyroptosis is delineated., Method: Rats were challenged with a single intrarectal dose of acetic acid (AA) solution (2 ml; 4 % v/v) to induce colitis. RDV (20 mg/kg, ip) and sulfasalazine (100 mg/kg, po) were administered to rats 14 days before the injection of AA., Results: Administration of RDV ameliorated colonic cell injury and loss as manifested by improvement of severe colon histopathological mutilation and macroscopic damage and disease activity index scores together with restoration of normal colon weight/length ratio. In addition, RDV alleviated colonic inflammatory reactions, thereby curtailing NF-κB activation and the inflammatory cytokines, TNF-α, IL-18, and IL-1β. Mitigation of colonic oxidative stress and apoptotic reactions were also evident in the setting of RDV treatment. Mechanistically, RDV enhanced the anti-inflammatory cascade, SIRT6/FoxC1, together with curbing the pyroptotic signal, NLRP3/cleaved caspase-1/Gasdermin D-elicited colonic inflammatory cell death., Conclusion: This study reveals, for the first time, the anti-inflammatory effect of RDV against experimental UC. Augmenting SIRT6/FoxC1-mediated repression of colonic inflammation and pyroptosis might advocate the colo-protective potential of RDV., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: Colorectal cancer progression involves complex cellular mechanisms. This study examines the effects of Lactobacillus plantarum-derived extracellular vesicles (LEVs) on the SIRT5/p53 axis, focusing on glycolytic metabolic reprogramming and abnormal proliferation in intestinal epithelial cells., Methods: LEVs were isolated from Lactobacillus plantarum and incubated with Caco-2 cells. Differential gene expression was analyzed through RNA sequencing and compared with TCGA-COAD data. Key target genes and pathways were identified using PPI network and pathway enrichment analysis. Various assays, including RT-qPCR, EdU staining, colony formation, flow cytometry, and Western blotting, were used to assess gene expression, cell proliferation, and metabolic changes. Co-immunoprecipitation confirmed the interaction between SIRT5 and p53, and animal models were employed to validate in vivo effects., Results: Bioinformatics analysis indicated the SIRT5/p53 axis as a critical pathway in LEVs' modulation of colorectal cancer. LEVs were found to inhibit colorectal cancer cell proliferation and glycolytic metabolism by downregulating SIRT5, influencing p53 desuccinylation. In vivo, LEVs regulated this axis, reducing tumor formation in mice. Clinical sample analysis showed that SIRT5 and p53 succinylation levels correlated with patient prognosis., Conclusion: Lactobacillus-derived extracellular vesicles play a pivotal role in suppressing colonic tumor formation by modulating the SIRT5/p53 axis. This results in decreased glycolytic metabolic reprogramming and reduced proliferation in intestinal epithelial cells., (© 2024. The Author(s).)

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have a variety of cardiovascular and renoprotective effects and have been developed as novel agents for the treatment of heart failure. However, the beneficial mechanisms of SGLT2i on cardiac tissue need to be investigated further. In this study, we established a mouse model of acute myocardial infarction (AMI) using coronary artery constriction surgery and investigated the role of dapagliflozin (DAPA) in protecting cardiomyocytes from hypoxic injury induced by AMI. In vitro experiments were done using hypoxic cultured H9c2 ventricular cells to verify this potential mechanism. Expression of the SIRT family and related genes and proteins was verified by qPCR, Western blotting and immunofluorescence staining, and the intrinsic potential mechanism of cardiomyocyte death due to AMI and hypoxia was comprehensively investigated by RNA sequencing. The RNA sequencing results of cardiomyocytes from AMI mice showed that the SIRT family may be mainly involved in the mechanisms of hypoxia-induced cardiomyocyte death. In vitro hypoxia-induced ventricular cells showed the role of dapagliflozin in conferring resistance to hypoxic injury in cardiomyocytes. It showed that SIRT1/3/6 were downregulated in H9c2 cells in a hypoxic environment, and the addition of dapagliflozin significantly increased the gene and protein expression of SIRT1, 3 and 6. We then verified the underlying mechanisms induced by dapagliflozin in hypoxic cardiomyocytes using RNA-seq, and found that dapagliflozin upregulated the hypoxia-induced gene downregulation, which includes ESRRA , EPAS1 , AGTRAP , etc., that associated with SIRTs-related and apoptosis-related signaling to prevent H9c2 cell death. This study provides laboratory data for SGLT2i dapagliflozin treatment of AMI and confirms that dapagliflozin can be used to treat hypoxia-induced cellular necrosis in cardiomyocytes, in which SIRT1 and SIRT3 may play an important role. This opens up further opportunities for SGLT2i in the treatment of heart disease.

Background: Sirtuin 7 (SIRT7) is pivotal in diverse diseases progression. Importantly, SIRT7 is associated with melanin production. However, whether SIRT7 regulates vitiligo is unclear. Therefore, we aimed to investigate the effects of SIRT7 on pigmentation and the modification of glucose 6-phosphate dehydrogenase (G6PD)., Methods: After knockdown SIRT7 and G6PD, pigmentation of melanocytes was evaluated using commercial kits, immunofluorescence, and Western blot analysis. The succinylation of G6PD mediated by SIRT7 was analyzed using co-immunoprecipitation, immunofluorescence, Western blot analysis, and cycloheximide-chase experiment., Results: We found that SIRT7 was highly expressed in vitiligo skin lesions. Knockdown of SIRT7 increased tyrosinase activity, melanin content, and the levels of α-melanocyte-stimulating hormone, MITF, TYR, TRP1, and TRP2. Additionally, SIRT7 directly interacted with G6PD. Silenced SIRT7 promoted the succinylation of G6PD and enhanced its protein stability. G6PD knockdown reversed the effect of reduced SIRT7 expression on melanin production., Conclsuion: Silencing of SIRT7 promotes pigmentation of melanocytes by succinylating G6PD, suggesting that SIRT7-mediated G6PD desuccinylation may promote vitiligo progression., (© 2024 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.)

This review focuses on the vital function that SIRT1 and other sirtuins play in promoting cellular senescence in vascular smooth muscle cells, which is a key element in the pathogenesis of vascular aging and associated cardiovascular diseases. Vascular aging is a gradual process caused by the accumulation of senescent cells, which results in increased vascular remodeling, stiffness, and diminished angiogenic ability. Such physiological alterations are characterized by a complex interplay of environmental and genetic variables, including oxidative stress and telomere attrition, which affect gene expression patterns and trigger cell growth arrest. SIRT1 has been highlighted for its potential to reduce cellular senescence through modulation of multiple signaling cascades, particularly the endothelial nitric oxide (eNOS)/NO signaling pathway. It also modulates cell cycle through p53 inactivation and suppresses NF-κB mediated expression of adhesive molecules at the vascular level. The study also examines the therapeutic potential of sirtuin modulation in vascular health, identifying SIRT1 and its sirtuin counterparts as potential targets for reducing vascular aging. This study sheds light on the molecular basis of vascular aging and the beneficial effects of sirtuins, paving the way for the development of tailored therapies aimed at enhancing vascular health and prolonging life., Competing Interests: Declaration of Competing Interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Cadmium (Cd) is a neurotoxic contaminant that induces cognitive decline similar to that observed in Alzheimer's disease (AD). Autophagic flux dysfunction is attributed to the pathogenesis of AD, and this study aimed to investigate the effect of autophagy on environmental Cd-induced AD progression and the underlying mechanism. Here, Cd exposure inhibited autophagosome-lysosome fusion and impaired lysosomal function, leading to defects in autophagic clearance and then to APP accumulation and nerve cell death. Proteomic analysis coupled with Ingenuity Pathway Analysis (IPA) identified SIRT5 as an essential molecular target in Cd-impaired autophagic flux. Mechanistically, Cd exposure hampered the expression of SIRT5, thus increasing the succinylation of RAB7A at lysine 31 and inhibiting RAB7A activity, which contributed to autophagic flux blockade. Importantly, SIRT5 overexpression led to the restoration of autophagic flux blockade, the alleviation of Aβ deposition and memory deficits, and the desuccinylation of RAB7A in Cd-exposed FAD 4T mice. Additionally, SIRT5 levels decrease mainly in neurons but not in other cell clusters in the brains of AD patients according to single-nucleus RNA sequencing data from the public dataset GSE188545. This study reveals that SIRT5-catalysed RAB7A desuccinylation is an essential adaptive mechanism for the amelioration of Cd-induced autophagic flux blockade and AD-like pathogenesis., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Abstract: Sepsis-induced acute kidney injury (SAKI) poses a significant clinical challenge with high morbidity and mortality. Excessive mitochondrial fission has been identified as the central pathogenesis of sepsis-associated organ damage, which is also implicated in the early stages of SAKI. Sirtuin 5 (SIRT5) has emerged as a central regulator of cellular mitochondrial function; however, its role in the regulation of sepsis-induced excessive mitochondrial fission in kidney and the underlying mechanism remains unclear. In this study, SAKI was modeled in mice through cecal ligation and puncture, and in human renal tubular epithelial (HK-2) cells stimulated with lipopolysaccharide (LPS), to mimic the cell SAKI model. Our findings revealed that septic mice with a SIRT5 knockout exhibited shortened survival times and elevated levels of renal injury compared to wild-type mice, suggesting the significant involvement of SIRT5 in SAKI pathophysiology. Additionally, we observed that SIRT5 depletion led to increased renal mitochondrial fission, while the use of a mitochondrial fission inhibitor (Mdivi-1) reversed the detrimental effects caused by SIRT5 depletion, emphasizing the pivotal role of SIRT5 in preventing excessive mitochondrial fission. In vitro experiments demonstrated that the overexpression of SIRT5 effectively mitigated the adverse effects of LPS on HK-2 cells viability and mitochondrial fission. Conversely, downregulation of SIRT5 decreased HK-2 cells viability and exacerbated LPS-induced mitochondrial fission. Mechanistically, the protective function of SIRT5 may be in part, ascribed to its desuccinylating action on ATPase inhibitory factor 1. In conclusion, this study provides novel insights into the underlying mechanisms of SAKI, suggesting the possibility of identifying future drug targets in terms of improved mitochondrial dynamics by SIRT5., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by the Shock Society.)

Sirtuin 6 (SIRT6) can inhibit the fibrosis of many organs. However, the relationship between SIRT6 and peritoneal fibrosis (PF) in peritoneal dialysis (PD) remains unclear. We collected 110 PD patients with a duration of PD for more than 3 months and studied the influence of PD duration and history of peritonitis on SIRT6 levels in PD effluents (PDEs). We also analyzed the relationship between SIRT6 levels in PDEs and transforming growth factor beta 1 (TGF-β1), IL-6, PD duration, peritoneal function, PD ultrafiltration (UF), and glucose exposure. We extracted human peritoneal mesothelial cells (HPMCs) from PDEs and measured the protein and gene expression levels of SIRT6, E-cadherin, vimentin, and TGF-β1 in these cells. Based on the clinical results, we used human peritoneal mesothelial cells lines (HMrSV5) to observe the changes in SIRT6 levels and mesothelial-to-mesenchymal transition (MMT) after intervention with PD fluid. By overexpressing and knocking down SIRT6 expression, we investigated the effect of SIRT6 expression on E-cadherin, vimentin, and TGF-β1 expression to elucidate the role of SIRT6 in mesothelial-to-epithelial transition in PMCs. Results: (1) With the extension of PD duration, the influence of infection on SIRT6 levels in PDEs increased. Patients with the PD duration of more than 5 years and a history of peritonitis had the lowest SIRT6 levels. (2) SIRT6 levels in PDEs were negatively correlated with PD duration, total glucose exposure, TGF-β1, IL-6 levels, and the dialysate-to-plasma ratio of creatinine (Cr4hD/P), but positively correlated with UF. This indicates that SIRT6 has a protective effect on the peritoneum. (3) The short-term group (PD ≤ 1 year) had higher SIRT6 and E-cadherin gene and protein levels than the mid-term group (1 year < PD ≤ 5 years) and long-term group (PD > 5 years) in PMCs, while vimentin and TGF-β1 levels were lower in the mid-term group and long-term group. Patients with a history of peritonitis had lower SIRT6 and E-cadherin levels than those without such a history. (4) After 4.25% PD fluid intervention for HPMCs, longer intervention time resulted in lower SIRT6 levels. (5) Overexpressing SIRT6 can lead to increased E-cadherin expression and decreased vimentin and TGF-β1 expression in HPMCs. Knocking down SIRT6 expression resulted in decreased E-cadherin expression and increased vimentin and TGF-β1 expression in HPMCs. This indicates that SIRT6 expression can inhibit MMT in HPMCs, alleviate PF associated with PD, and have a protective effect on the peritoneum., (© 2024. The Author(s).)

Stem cells persist throughout the lifespan to repair and regenerate tissues due to their unique ability to self-renew and differentiate. Here we reflect on the recent discoveries in stem cells that highlight a mitochondrial metabolic checkpoint at the restriction point of the stem cell cycle. Mitochondrial activation supports stem cell proliferation and differentiation by providing energy supply and metabolites as signaling molecules. Concomitant mitochondrial stress can lead to loss of stem cell self-renewal and requires the surveillance of various mitochondrial quality control mechanisms. During aging, a mitochondrial protective program mediated by several sirtuins becomes dysregulated and can be targeted to reverse stem cell aging and tissue degeneration, giving hope for targeting the mitochondrial metabolic checkpoint for treating tissue degenerative diseases., Competing Interests: Declaration of interests The authors have no interests to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Aging affects all organs. Arteries, in particular, are among the most affected. Vascular aging (VA) is defined as age-associated changes in function and structure of vessels. Classical VA phenotypes are carotid intima-media thickness (IMT), carotid plaque (CP), and arterial stiffness (STIFF). Individuals have different predisposition to these VA phenotypes and their associated risk of cardiovascular events. Some develop an early vascular aging (EVA), and others are protected and identified as having supernormal vascular aging (SUPERNOVA). The mechanisms leading to these phenotypes are not well understood. In the Northern Manhattan Study (NOMAS), we found genetic variants in the 7 Sirtuins (SIRT) and 5 Uncoupling Proteins (UCP) to be differently associated with risk to developing VA phenotypes. In this article, we review the results of genetic-epidemiology studies to better understand which of the single nucleotide polymorphisms (SNPs) in SIRT and UCP are responsible for both EVA and SUPERNOVA., Competing Interests: Declaration of competing interest Declarations of interest: none., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Huntington's disease (HD) is an autosomal inherited progressive neurodegenerative disorder which is caused by the CAG trinucleotide repeat in the huntingtin gene. The mutation induces mitochondrial dysfunction in neurons, which leads to striatal neuronal loss. The efficacy of the available therapies is limited, thus acquisition of more data about the pathomechanism of HD and development of new strategies is urgent. Sirtuins (Sirt1-7) belong to the histone deacetylase family, and interestingly they have been associated with HD, however, their role in HD is still not fully understood. To clarify the role of sirtuins in HD, we utilized a 3-nitropropionic acid (3-NP) induced HD model and assessed alterations in gene expression using RT-PCR. Moreover, we studied the extension of neurodegeneration in the striatum, and behavioural changes. Furthermore, we involved Sirt3 knockout (Sirt3KO) mice to investigate the impact of Sirt3 deficiency in the expression of the other sirtuins. Our results showed that with 3-NP treatment, the mRNA level of Sirt2,5,7 changed significantly in wild-type (WT) mice, whereas in Sirt3KO animals there was no change. Interestingly, Sirt3 deficiency did not exacerbate 3-NP-mediated striatal neuronal loss, while Sirt3KO animals showed higher mortality than WT littermates. However, the absence of Sirt3 did not affect the behaviour of animals. Finally, we demonstrated that the changes in the expression of sirtuins are age- and sex- dependent. According to our findings, there is evidence that Sirt3 has a major impact on the regulation of other sirtuin isoforms, survival and neuroprotection. However, this neuroprotective effect does not manifest in the behaviour., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Non-neovascular or dry age-related macular degeneration (AMD) is a multi-factorial disease with degeneration of the aging retinal-pigmented epithelium (RPE). Lysosomes play a crucial role in RPE health via phagocytosis and autophagy, which are regulated by transcription factor EB/E3 (TFEB/E3). Here, we find that increased AKT2 inhibits PGC-1α to downregulate SIRT5, which we identify as an AKT2 binding partner. Crosstalk between SIRT5 and AKT2 facilitates TFEB-dependent lysosomal function in the RPE. AKT2/SIRT5/TFEB pathway inhibition in the RPE induced lysosome/autophagy signaling abnormalities, disrupted mitochondrial function and induced release of debris contributing to drusen. Accordingly, AKT2 overexpression in the RPE caused a dry AMD-like phenotype in aging Akt2 KI mice, as evident from decline in retinal function. Importantly, we show that induced pluripotent stem cell-derived RPE encoding the major risk variant associated with AMD (complement factor H; CFH Y402H) express increased AKT2, impairing TFEB/TFE3-dependent lysosomal function. Collectively, these findings suggest that targeting the AKT2/SIRT5/TFEB pathway may be an effective therapy to delay the progression of dry AMD., (© 2024. The Author(s).)

Background: Obesity is a major health burden. Preadipocytes proliferate and differentiate in mature adipocytes in the adipogenic process, which could be a potential therapeutic approach for obesity. Deficiency of SIRT6, a stress-responsive protein deacetylase and mono-ADP ribosyltransferase enzyme, blocks adipogenesis. Mutants of SIRT6 (N308K/A313S) were recently linked to the in the long lifespan Ashkenazi Jews. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect adipogenesis at the transcriptional and epigenetic level., Methods: We analyzed the role of SIRT6 wild-type (WT) or SIRT6 centenarian-associated mutant (N308K/A313S) overexpression in adipogenesis, by creating stably transduced preadipocyte cell lines using lentivirus on the 3T3-L1 model. Histone post-translational modifications (PTM: acetylation, methylation) and transcriptomic changes were analyzed by mass spectrometry (LC-MS/MS) and RNA-Seq, respectively, in 3T3-L1 adipocytes. In addition, the adipogenic process and related signaling pathways were investigated by bioinformatics and biochemical approaches., Results: Overexpression of centenarian-associated SIRT6 mutant increased adipogenic differentiation to a similar extent compared to the WT form. However, it triggered distinct histone PTM profiles in mature adipocytes, with significantly higher acetylation levels, and activated divergent transcriptional programs, including those dependent on signaling related to the sympathetic innervation and to PI3K pathway. 3T3-L1 mature adipocytes overexpressing SIRT6 N308K/A313S displayed increased insulin sensitivity in a neuropeptide Y (NPY)-dependent manner., Conclusions: SIRT6 N308K/A313S overexpression in mature adipocytes ameliorated glucose sensitivity and impacted sympathetic innervation signaling. These findings highlight the importance of targeting SIRT6 enzymatic activities to regulate the co-morbidities associated with obesity., (© 2024. The Author(s).)

Background: Long noncoding RNAs (lncRNAs) play vital regulatory functions in non-small cell lung cancer (NSCLC). Cisplatin (DDP) resistance has significantly decreased the effectiveness of DDP-based chemotherapy in NSCLC patients. This study aimed to investigate the effects of SH3PXD2A antisense RNA 1 (SH3PXD2A-AS1) on DDP resistance in NSCLC., Methods: Proliferation and apoptosis of DDP-resistant NSCLC cells were detected using cell counting kit-8 and flow cytometry assays. The interaction between SH3PXD2A-AS1 and sirtuin 7 (SIRT7) was assessed using co-immunoprecipitation (Co-IP), RNA pull-down, RNA immunoprecipitation (RIP), RNA fluorescence in situ hybridization, and immunofluorescence assays, while succinylation (SUCC) of Forkhead Box M1 (FOXM1) was analyzed by IP and Western blot assays. The role of SH3PXD2A-AS1 in vivo was explored using a xenografted tumor model., Results: Expression of SH3PXD2A-AS1 was found elevated in DDP-resistant NSCLC cells, while it's knocking down translated into suppression of cell viability and promotion of apoptosis. Moreover, silencing of SH3PXD2A-AS1 resulted in decreased FOXM1 protein level and enhanced FOXM1-SUCC protein level. The SIRT7 was found to interact with FOXM1, translating into inhibition of FOXM1 SUCC at the K259 site in human embryonic kidney (HEK)-293T cells. Overexpressing of SIRT7 reversed the increase of FOXM1-SUCC protein level and apoptosis, and the decrease of cell viability induced by silencing of SH3PXD2A-AS1. In tumor-bearing mice, SH3PXD2A-AS1 inhibition suppressed tumor growth and the protein levels of Ki67, SIRT7, and FOXM1., Conclusion: SH3PXD2A-AS1 promoted DDP resistance in NSCLC cells by regulating FOXM1 SUCC via SIRT7, offering a promising therapeutic approach for NSCLC., (© 2024. The Author(s).)

With increasing research, the sirtuin (SIRT) protein family has become increasingly understood. Studies have demonstrated that SIRTs can aid in metabolism and affect various physiological processes, such as atherosclerosis, heart failure (HF), hypertension, type 2 diabetes, and other related disorders. Although the pathogenesis of HF with preserved ejection fraction (HFpEF) has not yet been clarified, SIRTs have a role in its development. Therefore, SIRTs may offer a fresh approach to the diagnosis, treatment, and prevention of HFpEF as a novel therapeutic intervention target.

To assess and validate the gene expression profile of SIRTs (SIRT1, SIRT2, SIRT3, SIRT4, SIRT5, SIRT6, and SIRT7) in relation to the pathogenesis and prognostic progression of Myelodysplastic neoplasm (MDS). Eighty bone marrow samples of patients with de novo MDS were diagnosed according to WHO 2022 and IPSS-R criteria. Ten bone marrow samples were obtained from elderly healthy volunteers and used as control samples. Gene expression levels of all SIRTs were assessed using RT-qPCR assays. Downregulation of SIRT2 (p = 0.009), SIRT3 (p = 0.048), SIRT4 (p = 0.049), SIRT5 (p = 0.046), SIRT6 (p = 0.043), and SIRT7 (p = 0.047) was identified in MDS patients compared to control individuals. Also, we identified that while SIRT2-7 genes are typically down-regulated in MDS patients compared to normal controls, there are relative expression variations among MDS patient subgroups. Specifically, SIRT4 (p = 0.029) showed increased expression in patients aged 60 or above, and both SIRT2 (p = 0.016) and SIRT3 (p = 0.036) were upregulated in patients with hemoglobin levels below 8 g/dL. SIRT2 (p = 0.045) and SIRT3 (p = 0.033) were highly expressed in patients with chromosomal abnormalities. Different SIRTs exhibited altered expression patterns concerning specific MDS clinical and prognostic characteristics. The downregulation in SIRTs genes (e.g., SIRT2 to SIRT7) expression in Brazilian MDS patients highlights their role in the disease's development. The upregulation of SIRT2 and SIRT3 in severe anemia patients suggests a potential link to manage iron overload-related complications in transfusion-dependent patients. Moreover, the association of SIRT2/SIRT3 with genomic instability and their role in MDS progression signify promising areas for future research and therapeutic targets. These findings underscore the importance of SIRT family in understanding and addressing MDS, offering novel clinical, prognostic, and therapeutic insights for patients with this condition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Keloid, a fibroproliferative disorder, significantly impacts patients' quality of life, yet effective therapies remain elusive. This study explored the role of silent information regulator 6 (SIRT6) in modulating the proliferation, invasion, and collagen synthesis of keloid fibroblasts., Methods: Keloid and normal skin specimens were collected, and fibroblasts were isolated from the keloid tissue. SIRT6 recombinant adenovirus (Ad) was constructed to infect keloid fibroblasts to overexpress SIRT6. This study entails three groups: Control group, adenovirus-Negative Control (Ad-NC) group, and Ad-SIRT6 group. SIRT6 protein and mRNA levels were measured via Western blotting and Quantitative reverse transcription polymerase chain reaction (qRT-PCR), respectively. Cell viability was determined using 5-ethynyl-2'-deoxyuridine (EdU) assay. Flow cytometry was exploited to measure cell apoptosis. To investigate cell migration, wound healing assay and Transwell assay were employed. Western blotting was also utilized to study the expression levels of apoptotic proteins, collagen deposition-related proteins, and Mitogen-Activated Protein Kinases (MAPK)/extracellular regulated protein kinases (ERK) pathway-related proteins., Results: Compared to the control and Ad-NC groups, the Ad-SIRT6 group exhibited significantly elevated SIRT6 level; diminished cell proliferation, migration and invasion; reduced protein levels of α-smooth muscle actin (α-SMA), collagen I, collagen III, phospho SMAD Family Member 3 (p-Smad3), transforming growth factor-β 1 (TGF-β1), and MAPK/ERK pathway proteins (phospho extracellular signal-regulated protein kinase 1/2 (p-ERK1/2), phospho MAP kinase-ERK kinase (p-MEK) and phospho-c-Raf (p-c-Raf)). Treatment with epidermal growth factor (EGF), an MAPK/ERK pathway agonists, reversed the inhibitory effect of SIRT6 on cell activity and inhibited apoptosis in keloid fibroblasts., Conclusion: SIRT6 overexpression in keloid fibroblasts attenuates proliferation, invasion, and collagen synthesis, while fostering apoptosis, likely through the suppression of MAPK/ERK pathway activity. This suggests a potential therapeutic target for keloid treatment.

Objective: Acute pancreatitis (AP) stands as a frequent cause for clinical emergency hospital admissions. The X-box binding protein 1 (XBP1) was found to be implicated in pancreatic acinar cell apoptosis. The objective is to unveil the potential mechanisms governed by XBP1 and SIRT6 in the context of AP., Methods: Caerulein-treated human pancreatic duct epithelial (HPDE) cells to establish an in vitro research model. The levels and regulatory role of SIRT6 in the treated cells were evaluated, including its effects on inflammatory responses, oxidative stress, apoptosis, and endoplasmic reticulum stress. The relationship between XBP1 and SIRT6 was explored by luciferase and ChIP experiments. Furthermore, the effect of XBP1 overexpression on the regulatory function of SIRT6 on cells was evaluated., Results: Caerulein promoted the decrease of SIRT6 and the increase of XBP1 in HPDE cells. Overexpression of SIRT6 slowed down the secretion of inflammatory factors, oxidative stress, apoptosis level, and endoplasmic reticulum stress in HPDE cells. However, XBP1 negatively regulated SIRT6, and XBP1 overexpression partially reversed the regulation of SIRT6 on the above aspects., Conclusion: Our study illuminates the role of XBP1 in downregulating SIRT6 in HPDE cells, thereby promoting cellular injury. Inhibiting XBP1 or augmenting SIRT6 levels holds promise in preserving cell function and represents a potential therapeutic avenue in the management of AP., (© 2024 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.)

Background/aim: Glutamine metabolism is crucial in cell proliferation, aging, and apoptosis across various cancer types. Existing research indicates that Sirtuin 4 (SIRT4), primarily located in mitochondria, modulates this process. This study aimed to clarify the regulatory relationship between SIRT4 and glutamine metabolism in cervical cancer., Materials and Methods: SIRT4 mRNA levels and their clinical correlation to cervical cancer were analyzed using the UALCAN database. Immunohistochemistry (IHC) was performed to assess SIRT4 protein expression in tissue samples from cervical cancer patients. Transient transfection was employed to create Hela and Siha cell lines with overexpressed SIRT4, mitogen-activated extracellular signal-regulated kinase (MEK), and glutaminase 1 (GLS1). The impact on cellular functions was studied using MTT, soft agar, transwell, and western blotting assays. Glutamate and ATP levels were also measured to evaluate metabolic changes., Results: Low levels of SIRT4 mRNA in cervical cancer tissues correlated with tumor metastasis and poor survival rates. Overexpression of SIRT4 led to suppressed cell proliferation, colony growth, and motility, along with significant down-regulation of GLS expression, a key contributor to glutamine metabolism. Additionally, SIRT4 overexpression resulted in the inactivation of the MEK/ERK/c-myc signaling pathway, while overexpression of MEK reversed these effects. Notably, the inhibitory effects of SIRT4 on cell proliferation, colony formation, migration, and invasion in Hela and Siha cells were significantly attenuated following GLS1 overexpression., Conclusion: SIRT4 acts as an anti-cancer agent in cervical cancer by inhibiting glutamine metabolism through the MEK/ERK/c-myc signaling pathway, providing a novel sight for cervical cancer therapy., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Zn 2+ levels are reported to be correlated with kidney function. We explored the significance of Zn 2+ in sepsis-induced acute kidney injury (SI-AKI) through the regulation of sirtuin 7 (SIRT7) activity. The sepsis rat model was established by cecal ligation and perforation (CLP) and intraperitoneally injected with ZnSO 4 or SIRT7 inhibitor 97491 (SIRT7i), with renal tubular injury assessed by hematoxylin and eosin staining. In vitro, human renal tubular epithelial cells (HK-2) were induced with lipopolysaccharide to obtain a renal injury cell model, followed by ZnSO 4 or SIRT7i and autophagy inhibitor (3-methyladenine) treatment. Interleukin (IL)-1β, IL-18, reactive oxygen species (ROS), Parkin acetylation level, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were determined. The renal tubule injury, inflammation condition, and pyroptosis-related and autophagy-related protein levels were assessed. The pyroptosis in kidney tissues and autophagosome formation were observed by transmission electron microscopy. Zn 2+ alleviated renal injury in CLP rats and inhibited pyroptosis and its related protein levels by inhibiting SIRT7 activity in septic rat renal tissues. In vitro, Zn 2+ increased HK-2 cell viability and reduced KIM-1, NGAL, IL-1β, IL-18, NLRP3 inflammasome, cleaved caspase-1, gasdermin D-N levels, and pyroptotic cell number. Zn 2+ increased autophagosome number and LC3BII/LC3BI ratio and decreased TOM20, TIM23, P62, and mitochondrial ROS levels. Zn 2+ increased Parkin acetylation by repressing SIRT7 activity. Inhibiting mitophagy partially averted Zn 2+ -inhibited NLRP3 inflammasome activation and apoptosis in HK-2 cells. Zn 2+ upregulated Parkin acetylation by repressing SIRT7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving SI-AKI. NEW & NOTEWORTHY Zn 2+ upregulated Parkin acetylation by repressing sirtuin 7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving sepsis-induced acute kidney injury.

Acute kidney injury (AKI) is extremely prevalent among hospitalizations and presents a significant risk for the development of chronic kidney disease and increased mortality. Ischemia caused by shock, trauma, and transplant are common causes of AKI. To attenuate ischemic AKI therapeutically, we need a better understanding of the physiological and cellular mechanisms underlying damage. Instances of ischemia are most damaging in proximal tubule epithelial cells (PTECs) where hypoxic signaling cascades, and perhaps more rapidly, posttranslational modifications (PTMs), act in concert to change cellular metabolism. Here, we focus on the effects of the understudied PTM, lysine succinylation. We have previously shown a protective effect of protein hypersuccinylation on PTECs after depletion of the desuccinylase sirtuin5. General trends in the results suggested that hypersuccinylation led to upregulation of peroxisomal activity and was protective against kidney injury. Included in the list of changes was the Parkinson's-related deglycase Park7. There is little known about any links between peroxisome activity and Park7. In this study, we show in vitro and in vivo that Park7 has a crucial role in protection from AKI and upregulated peroxisome activity. These data in combination with published results of Park7's protective role in cardiovascular damage and chronic kidney disease lead us to hypothesize that succinylation of Park7 may ameliorate oxidative damage resulting from AKI and prevent disease progression. This novel mechanism provides a potential therapeutic mechanism that can be targeted. NEW & NOTEWORTHY Succinylation is an understudied posttranslational modification that has been shown to increase peroxisomal activity. Furthermore, increased peroxisomal activity has been shown to reduce oxidative stress and protect proximal tubules after acute kidney injury. Analysis of mass spectrometry succinylomic and proteomic data reveals a novel role for Parkinson's related Park7 in mediating Nrf2 antioxidant response after kidney injury. This novel protection pathway provides new insights for kidney injury prevention and development of novel therapeutics.

Background: Doxorubicin (DOX) is a widely utilized anthracycline chemotherapy drug in cancer treatment, yet its efficacy is hindered by both short-term and long-term cardiotoxicity. Although oxidative stress, inflammation and mitochondrial dysfunction are established factors in DOX-induced cardiotoxicity, the precise molecular pathways remain elusive. Further exploration of the pathogenesis and identification of novel molecular targets are imperative. Recent studies have implicated the Sirtuins family in various physiological and pathological processes, suggesting their potential in ameliorating DOX-induced cardiotoxicity. Moreover, research on Sirtuins has discovered small-molecule compounds or medicinal plants with regulatory effects, representing a notable advancement in preventing and treating DOX-induced cardiac injury., Purpose: In this review, we delve into the pathogenesis of DOX-induced cardiotoxicity and explore the therapeutic effects of Sirtuins in mitigating this condition, along with the associated molecular mechanisms. Furthermore, we delineate the roles and mechanisms of small-molecule regulators of Sirtuins in the prevention and treatment of DOX-induced cardiotoxicity., Study-Design/methods: Data for this review were sourced from various scientific databases (such as Web of Science, PubMed and Science Direct) up to March 2024. Search terms included "Sirtuins," "DOX-induced cardiotoxicity," "DOX," "Sirtuins regulators," "histone deacetylation," among others, as well as several combinations thereof., Results: Members of the Sirtuins family regulate both the onset and progression of DOX-induced cardiotoxicity through anti-inflammatory, antioxidative stress and anti-apoptotic mechanisms, as well as by maintaining mitochondrial stability. Moreover, natural plant-derived active compounds such as Resveratrol (RES), curcumin, berberine, along with synthetic small-molecule compounds like EX527, modulate the expression and activity of Sirtuins., Conclusion: The therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity represents a potential molecular target. However, further research is urgently needed to elucidate the relevant molecular mechanisms and to assess the safety and biological activity of Sirtuins regulators. This review offers an in-depth understanding of the therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity, providing a preliminary basis for the clinical application of Sirtuins regulators in this condition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier GmbH.)

Sirtuins are nicotinamide adenine dinucleotide (NAD + )-dependent protein lysine deacylases regulating metabolism and stress responses; however, characterization of the removed acyl groups and their downstream metabolic fates remains incomplete. Here we employed untargeted comparative metabolomics to reinvestigate mitochondrial sirtuin biochemistry. First, we identified N-glutarylspermidines as metabolites downstream of the mitochondrial sirtuin SIR-2.3 in Caenorhabditis elegans and demonstrated that SIR-2.3 functions as a lysine deglutarylase and that N-glutarylspermidines can be derived from O-glutaryl-ADP-ribose. Subsequent targeted analysis of C. elegans, mouse and human metabolomes revealed a chemically diverse range of N-acylspermidines, and formation of N-succinylspermidines and/or N-glutarylspermidines was observed downstream of mammalian mitochondrial sirtuin SIRT5 in two cell lines, consistent with annotated functions of SIRT5. Finally, N-glutarylspermidines were found to adversely affect C. elegans lifespan and mammalian cell proliferation. Our results indicate that N-acylspermidines are conserved metabolites downstream of mitochondrial sirtuins that facilitate annotation of sirtuin enzymatic activities in vivo and may contribute to sirtuin-dependent phenotypes., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Cutaneous squamous cell carcinoma (CSCC) is one of the most common types of skin cancer worldwide. Therefore, the identification of biomarkers associated with CSCC progression could aid in the early detection of high-risk squamous cell carcinoma and the development of novel therapeutic strategies., Objective: This study aimed to investigate the expression patterns of silent mating type Information Regulation 2 homolog 6 (SIRT6) in CSCC and its clinical significance., Methods: The protein expression level of SIRT6 in tissues was detected by immunohistochemistry, and the correlation between SIRT6 expression and clinicopathological parameters in CSCC patients was analyzed. The relative expression of SIRT6 in CSCC cell lineage and tissue specimens was determined by western blotting and PCR. The effect of SIRT6 silencing on cell proliferation was evaluated using cell counting kit 8. Wound healing, transwell method, and flow cytometry were used to investigate the migration, invasion, and cell cycle distribution/apoptosis of CSCC cells after SIRT6 silencing, respectively. Western blot was used to detect the expression of EMT (Epithelial-Mesenchymal Transition), cycle, apoptosis, and other related proteins., Results: The high expression of SIRT6 was correlated with the location of cancer tissue and Broder staging in CSCC patients. Knockdown of SIRT6 inhibited the proliferation, migration, invasion and EMT of CSCC cells, and promoted their apoptosis, with cells blocked in G1 phase., Study Limitations: No animal experiments were conducted to further verify the results., Conclusion: Decreased expression of SIRT6 can inhibit the occurrence and development of CSCC., (Copyright © 2024 Sociedade Brasileira de Dermatologia. Published by Elsevier España, S.L.U. All rights reserved.)

The time for diabetic nephropathy (DN) to progress from mild to severe is long. Thus, methods to continuously repress DN are required to exert long-lasting effects mediated through epigenetic regulation. In this study, we demonstrated the ability of nicotinamide adenine dinucleotide (NAD) and its metabolites to reduce albuminuria through Sirt1- or Nampt-dependent epigenetic regulation. We previously reported that proximal tubular Sirt1 was lowered before glomerular Sirt1. Repressed glomerular Sirt1 was found to epigenetically elevate Claudin-1. In addition, we reported that proximal tubular Nampt deficiency epigenetically augmented TIMP-1 levels in Sirt6-mediated pathways, leading to type-IV collagen deposition and diabetic fibrosis. Altogether, we propose that the Sirt1/Claudin-1 axis may be crucial in the onset of albuminuria at the early stages of DN and that the Nampt/Sirt6/TIMP-1 axis promotes diabetic fibrosis in the middle to late stages of DN. Finally, administration of NMN, an NAD precursor, epigenetically potentiates the regression of the onset of DN to maintain Sirt1 and repress Claudin-1 in podocytes, suggesting the potential use of NAD metabolites as epigenetic medications for DN., (© 2024. The Authors.)

SIRT6 is of interest for its promising effect in the treatment of aging-related diseases. Studies have shown quercetin (QUE) and its derivatives have varying degrees of effect on the catalytic effect of SIRT6. In the research, the effect of QUE on the protein-substrate interaction in the SIRT6-mediated mono-ADP ribosylation system was investigated by conventional molecular dynamics (MD) simulations combined with MM/PBSA binding free energy calculations. The results show that QUE can bind stably to SIRT6 with the binding energy of -22.8 kcal/mol and further affect the atomic interaction between SIRT6 and NAD + (or H3K9), resulting in an increased affinity between SIRT6-NAD + and decreased SIRT6-H3K9 binding capacity. At the same time, the binding of QUE can also alter some structural characteristics of the protein, with large shifts occurring in the residue regions involving the N-terminal (residues 1-27), Rossmann fold regions (residues 55-92), and ZBD (residues 164-179). Thus, QUE shows great potential as a scaffold for the design of novel potent SIRT6 modulators., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Aim: Acetaminophen (APAP) is clinically recommended as analgesic and antipyretic among pregnant women. However, accumulating laboratory evidence shows that the use of APAP during pregnancy may alter fetal development. Since fetal stage is a susceptible window for early oogenesis, we aim to assess the potential effects of maternal administration of APAP on fetal oocytes. Results: Pregnant mice at 14.5 dpc (days post-coitus) were orally administered with APAP (50 and 150mg/kg.bw/day) for 3 days; meanwhile, 14.5 dpc ovaries were collected and cultured with APAP or its metabolite N-acetyl-p-benzoquinone imine (NAPQI; 5 and 15 μ M ) for 3 days. It showed that APAP caused meiotic aberrations in fetal oocytes through its metabolite NAPQI, including meiotic prophase I (MPI) progression delay and homologous recombination defects. Co-treatment with nicotinamide (NAM) or nicotinamide riboside chloride (NRC), nicotinamide adenine dinucleotide (NAD + ) supplements, efficiently restored the MPI arrest, whereas the addition of the inhibitor of sirtuin 7 (SIRT7) invalidated the effect of the NAD + supplement. In addition, RNA sequencing revealed distorted transcriptomes of fetal ovaries treated with NAPQI. Furthermore, the fecundity of female offspring was affected, exhibiting delayed primordial folliculogenesis and puberty onset, reduced levels of ovarian hormones, and impaired developmental competence of MII oocytes. Innovation: These findings provide the first known demonstration that NAPQI, converted from maternal administration of APAP, disturbs meiotic process of fetal oocytes and further impairs female fecundity in adulthood. The concomitant oral dosing with NAM further supports the benefits of NAD + supplements on oogenesis. Conclusion: Short-term administration of APAP to pregnant mouse caused meiotic aberrations in fetal oocytes by its metabolite NAPQI, whereas co-treatment with NAD + supplement efficiently relieves the adverse effects by interacting with SIRT7.

Rationale: The disruption of the balance between fatty acid (FA) uptake and oxidation (FAO) leads to cardiac lipotoxicity, serving as the driving force behind diabetic cardiomyopathy (DbCM). Sirtuin 5 (Sirt5), a lysine de-succinylase, could impact diverse metabolic pathways, including FA metabolism. Nevertheless, the precise roles of Sirt5 in cardiac lipotoxicity and DbCM remain unknown., Objective: This study aims to elucidate the role and underlying mechanism of Sirt5 in the context of cardiac lipotoxicity and DbCM., Methods and Results: The expression of myocardial Sirt5 was found to be modestly elevated in diabetic heart failure patients and mice. Cardiac dysfunction, hypertrophy and lipotoxicity were exacerbated by ablation of Sirt5 but improved by forced expression of Sirt5 in diabetic mice. Notably, Sirt5 deficiency impaired FAO without affecting the capacity of FA uptake in the diabetic heart, leading to accumulation of FA intermediate metabolites, which mainly included medium- and long-chain fatty acyl-carnitines. Mechanistically, succinylomics analyses identified carnitine palmitoyltransferase 2 (CPT2), a crucial enzyme involved in the reconversion of fatty acyl-carnitines to fatty acyl-CoA and facilitating FAO, as the functional succinylated substrate mediator of Sirt5. Succinylation of Lys424 in CPT2 was significantly increased by Sirt5 deficiency, leading to the inactivation of its enzymatic activity and the subsequent accumulation of fatty acyl-carnitines. CPT2 K424R mutation, which mitigated succinylation modification, counteracted the reduction of enzymatic activity in CPT2 mediated by Sirt5 deficiency, thereby attenuating Sirt5 knockout-induced FAO impairment and lipid deposition., Conclusions: Sirt5 deficiency impairs FAO, leading to cardiac lipotoxicity in the diabetic heart through the succinylation of Lys424 in CPT2. This underscores the potential roles of Sirt5 and CPT2 as therapeutic targets for addressing DbCM., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

SIRT6, a key member of the sirtuin family, plays a pivotal role in regulating a number of vital biological processes, including energy metabolism, oxidative stress, and immune system modulation. Nevertheless, the function of SIRT6 in bony fish, particularly in the context of antiviral immune response, remains largely unexplored. In this study, a sirt6 was cloned and characterized in a commercial fish, the Chinese perch (Siniperca chuatsi). The SIRT6 possesses conserved SIR2 domain with catalytic core region when compared with other vertebrates. Tissue distribution analysis indicated that sirt6 was expressed in all detected tissues, and the sirt6 was significantly induced following infection of infectious haemorrhagic syndrome virus (IHSV). The overexpression of SIRT6 resulted in significant upregulation of interferon-stimulated genes (ISGs), such as viperin, mx, isg15, irf3 and ifp35, and inhibited viral replication. It was further found that SIRT6 was located in nucleus and could enhance the expression of ISGs induced by type I and II IFNs. These findings may provide new information in relation with the function of SIRT6 in vertebrates, and with viral prevention strategy development in aquaculture., Competing Interests: Declaration of competing interesti The authors confirm that they have no known financial conflicts of interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: Hypertensive disorder complicating pregnancy (HDCP) is a serious clinical disorder syndrome during pregnancy. This study aims at finding novel targets for HDCP therapy., Methods: HDCP-related mRNAs were firstly screened out and subjected to gene enrichment analysis. We chose protein kinase AMP-activated catalytic subunit alpha 2 (PRKAA2) as the research object. Thirty-nine HDCP patients at 32 to 40 weeks of gestation were selected as the HDCP group, and 39 normal controls who received cesarean section delivery at 37-42 weeks of pregnancy were enrolled in this study. Chorionic villi samples were collected within 30 min of delivery. The apoptosis of isolated placental trophoblasts was monitored to investigate the regulatory role of PRKAA2., Results: PRKAA2 expression was further proven to be enhanced in the placental tissues of HDCP patients compared with that of normal puerpera. Subsequently, the results of flow cytometry analysis and western blot indicated that PRKAA2 overexpression accelerated primary placental cell apoptosis, while its knockdown attenuated cell apoptosis. Mechanistically, we determined that the level of PRKAA2 succinylation was elevated in the placental tissue of HDCP patients. Through in vitro succinylation assay and mutagenesis, we confirmed that sirtuin 5 (SIRT5) interacts with PRKAA2 at K69 and K260 to induce PRKAA2 desuccinylation. SIRT5 regulated primary HDCP cell apoptosis through PRKAA2. Finally, the animal study revealed that PRKAA2 elevates the systolic blood pressure of HDCP rat model., Conclusion: Our findings indicated that SIRT5-mediated PRKAA2 succinylation modulates placental cell apoptosis in HDCP, suggesting that PRKAA2 is a potential therapeutic target for HDCP treatment.

Ethnopharmacological Relevance: Ligustrum lucidum W.T. Aiton is a traditional Chinese medicine that has long been used with high hepatoprotective therapeutic and condition value. Specnuezhenide (SP), the standard prominent secoiridoid compound of Fructus Ligustri Lucidi may ameliorate hepatic inflammation in chronic liver diseases., Aim of the Study: Regulating inflammation through SIRT6-P2X7R axis has caused the emergence of novel molecular mechanism strategies for reversing hepatic fibrosis. This study focused on the mechanism of SP in modulating the liver inflammatory microenvironment in hepatic fibrosis., Materials and Methods: C57BL/6 mice with hepatic fibrosis were stimulated with thioacetamide (TAA) prior to administration of SP. Hepatic stellate cells (HSCs) or normal mouse primary hepatocytes were exposed to transforming growth factor-β (TGF-β) treatment. Meanwhile, normal mouse bone marrow-derived macrophages (BMDMs) were treated with lipopolysaccharide/adenosine triphosphate (LPS/ATP), aiming to obtain the conditioned medium. HSCs and hepatocytes were transfected with SIRT6 knockdown vector (siRNA-SIRT6) to estimate the impact of SP on the SIRT6-P2X7R/NLRP3 signaling pathway., Results: SP suppressed the HSCs extracellular matrix (ECM) deposition as well as pro-inflammatory cytokine levels induced by the medium of BMDMs or TGF-β. In addition, SP also significantly up-regulated SIRT6, inhibited P2X7R-NLRP3 inflammasome in HSCs and hepatocytes, and functioned as MDL-800 (a SIRT6 agonist). SP reduced the hepatocytes pyroptosis and further prevented the occurrence of inflammatory response in the liver. SP could inhibit the activation of BMDMs and impede IL-1β and IL-18 from entering extracellular regions. Moreover, deficiency of SIRT6 in HSCs or hepatocytes reduced SP's regulation of P2X7R suppression. For TAA-treated mice, SP mitigated histopathological changes, ECM accumulation, EMT process, and NETs formation in hepatic fibrosis., Conclusions: Therefore, SP decreased inflammatory response via SIRT6-P2X7R/NLRP3 pathway and suppressed fibrillogenesis. These findings supported SP as the novel candidate to treat hepatic fibrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)